IMHO, live blade exercise is just nuts. Only two kinds of people do this: those that have been cut, and those who are going to be cut. There is no upside to this. Enough adrenaline should be available without resorting to an additional element of risk. Not only this, but you'll have a hard enough time controlling yourself to the degree necessary for this type of activity. What about the person holding the knife? How much can you control him? Really want your life depending on him? Don't become a statistic...